Adjuvant compositions

ABSTRACT

Acrylic acid polymer adjuvant compositions comprising a mixture of an acrylic acid polymer cross-linked with a polyallylsaccharide and a physiologically acceptable electrolyte have properties which greatly enhance the ease with which they may be formulated with active agents in the production of therapeutic mixtures of the adjuvant composition and active agent. Solutions of the therapeutic mixture have viscosities which are lowered to the point where they can be utilized commercially in a practical manner, while at the same time retaining the favorable adjuvant effects.

United States Patent [19] Lund [ Nov. 18, 1975 ADJUVANT COMPOSITIONS [75] Inventor: L10)"; J- Lund, Moraga, Calif.

[73 Assigneei Cutter Laboratories, Inc., Berkeley,

' Calif.

22 Filed: Dec. 30, 1974 21 Appl.No.:537,556

Related US. Application Data [63] Continuation-in-part of Ser. No. 317,752, Dec. 22, Y 1972, Pat. NO. 3,869,546v

'[301 Foreign Application Priority Data Dec. 12, 1973 United Kingdom 57602/73 Dec. 14, 1973 Germany 2362121 [52] US. Cl. 424/88; 424/89; 424/92;

[51] Int. Cl? A61K 27/12 [58] Field of Search 424/81, 88-92 '[56] References Cited I I UNITED STATES PATENTS 3,178,350 4/1965 Lund 424/89 3,469,003 9/1969 Hardy 424/89 3,639,577 2/1972 Urton et al. 424/92 3,869,546 3/1975 Lund 424/88 Primary Examiner-Shep K. Rose Attorney, Agent, or Firm-Millen, Raptes & White 7] ABSTRACT 9 Claims, 2 Drawing Figures U.S. Patent Nov. 18, 1975 3,920,811

LYOPHILIZED MIXTURE OF POLYALLYL- SACCHARIDE CROSS- LINKED ACRYLIC ACIDPOLYMER AND ELECTROLYTE STERILE SOLUTION OF POLYALLYLSACCHARIDE CROSS-LINKED ACRYLIC ACIDPOLYMER AND ELECTROLYTE ADJ UVANT COMPOSITIONS BACKGROUND OF THE INVENTION This is a continuation-in-part of application Ser. No. 317,752, filed Dec. 22, 1972 now U.S. Pat. No. 3,869,546.

This invention relates to adjuvants, more specifically to adjuvant compositions comprising an acrylic acid polymer cross-linked with polyallylsucros or polyallylpentaerythritol and to medicinal compositions comprising such adjuvants.

It is well established that the therapeutic effect of medicinal agents when administered subcutaneously or intramuscularly can be prolonged or enhanced by incorporating adjuvants with the medicinal agent. For example, antibody titers can be significantly enhanced in a host when an antigen is injected which has associated with it a substance which delays the-release and distribution of the antigen throughout the tissues of the host. Substances such as mineral oil and aluminum hydroxide produce this adjuvant effect. They serve several functions; namely, they adsorb the medicinal agent, as for example, an antigenic substance, and prevent rapid distribution of the antigen into surrounding tissues. Being relatively insoluble and non-metabolizable, they keep the antigen more or less localized at the site of injection so that the antigen is not quickly dispersed, thus giving the lymphocytes of the host an opportunity to generate antibodies. They also act as an irritant which promotes the routing of lymphocytes to the irritated site thus bringing the antibody producers in contact with the antigen. Such adjuvants, however, are not too satisfactory since they generally promote the formation of sterile abcesses and mineral oils may be implicated in the formation of tumors.

In U.S. Pat. No. Re. 26,963, reconstituted collagen is disclosed as a non-toxic adjuvant. It is stated that the collagen in the active agent-collagen combination, after injection, gels to a solid mass and retains the active agent in the injection site, a condition which favors retardation of the release of the active agent and hence allows the effect of the active agent to be maintained for a prolonged period of time. Furthermore, the observation is made that, at a given pH, the collagen may be dispersed in direct proportion to the'amount of sodium chloride added to it. The life of this adjuvant, hence its period of effectiveness, is decreased by the inclusion of sodium chloride.

The use of a polymer of acrylic acid cross-linked with various polyol compounds as an adjuvant is described in U.S. Pat. No. 3,178,350. Such polymers are commercially available under the trademark Carbopol. Carbopol 934, for example, is the polymer where the cross-linking agent is polyallylsucrose. Carbopol 941 is a lower molecular weight member of the class of Carbopols. These polymers form aqueous gels whose viscosity increases with increased pH or increased concentration of the Carbopol. According to the disclosure in U.S. Pat. No. 3,178,350, mixtures of Carbopol 934 or Carbopol 941 with various virus vaccines at about neutral pH, resulted in greatly enhanced antibody production in the host when the Carbopols were in the range of 0.25 to 0.50 per cent of the mixture. Unneutralized Carbopol was considerably less effective an adjuvant, probably because the antigen is destroyed at the low pH of the acidic Carbopol. It is believed that Carbopol behaves in a manner similar to other gels such as 2 collagen and aluminum hydroxide; namely, the active agent is adsorbed on the polymer and the combination is retained at the injection site. The polymer is only slowly dispersed and the active agent is retained at the juvant-biologic solution, because it was believed the adjuvant effect was achieved by high viscosity imparted to the adjuvant-biologic solution by the polymer.

It is known that electrolytes, e.g., benzoic acid, sodium benzoate, phenyl mercuric acetate as well as monovalent and polyvalent salts lower the viscosity of these polymers. See Drug and Cosmetic Indsutry, Oct. 1964: 95, 4, page 512.

U.S. Pat. Nos. 3,639,577 and 3,790,665 both disclose adjuvants containing Carbopol 934P and an antigen. However, in both patents, the Carbopol is employed in combination with an emulsion system and in U.S. Pat. No. 3,639,577, the adjuvant is a collagen-containing mixture.

Carbopol in its neutralized states, however, forms very viscous solutions or gels in the range of 0.2 or more percent after mixing with an active agent and is still too viscous to draw into and dispense from a hypodermic syringe with ease. Furthermore, the viscous nature of the material at these concentrations makes it very difficult to blend or mix uniformly with an active agent which is in a dry state or in an aqueous solution, particularly in production scale.

The excellent adjuvant properties of the carbopol cross-linked acrylic acid polymers would be most desirable if the high viscosity of useful ranges did not render it impracticable in formulation and dispensing operations.

It is a primary objective of this invention to provide effective adjuvant solutions of certain acrylic acid polymers while at the same time controlling the viscosity thereof to permit them to be readily mixed with an active agent and easily injected into a host.

A further object is to provide concentrated solutions of such polymers which may be easily mixed with solutions of active agents to give effective adjuvant mixtures without materially lowering the concentration of the active agent.

SUMMARY OF THE INVENTION The compositions of this invention are adjuvants for antigens which stimulate the production of antibodies consisting essentially of sterile and, as 0.1 1.0% aqueous solutions, injectable mixtures of a substantially neutralized polymer of acrylic acid cross-linked with from 0.75 to 2.00% of polyallylsucrose or polyallylpentaerythritol and an amount of a physiologically acceptable electrolyte'effective to lower substantially the viscosity of aqueous solutions of the adjuvants to a maximum of about 2,000 and about 50,000 cps, respectively, for 0.2 and 3% aqueops solutions thereof.

DETAILED DISCUSSION The viscosity of Carbopol type cross-linked acrylic acid polymer solutions can be reduced in accordance to this invention to a level which allows the solutions to be readily mixed with solid or solution forms of biologically active agents and allows the mixture to be easily dispensed through a hypodermic needle, by admixing an electrolyte with the polymer. It is known that an electrolyte, such as sodium chloride, increases the dispersibility of a collagen adjuvant. However, this increased dispersion, resulting from a decrease in viscosity, leads to a decrease in the adjuvant effect. It is also known that electrolytes will decrease the viscosity of Carbopol gels or solutions. On the basis of the detrimental effect that sodium chloride has on collagen, it would be expected that Carbopol would likewise become less effective as an adjuvant in the presence of an electrolyte. Therefore, it was of considerable surprise to discover that even though a solution of Carbopol whose viscosity had been greatly lowered by the inclusion of an electrolyte, this solution could be mixed with an active agent, an antigen for example, and the adjuvant effect of the polymer retained.

With reference to the drawings,

FIG. 1 is a conventional vial 1 sealed with a rubber stopper 2 which is covered with an aluminum cap 3 and containing therein a lyophilized mixture of polyallylsaccharide cross-linked acrylic acid polymer and electrolyte.

FIG. 2 is a sealed ampoule containing a sterile solution of polyallylsaccharide cross-linked acrylic acid polymer and electrolyte.

The adjuvant of this invention comprises an aqueous solution of a polymer as defined herein and a physiologically acceptable electrolyte, in a molar weight proportion of about 1 of the polymer (assuming a minimum molecular weight of about 200,000) to about 800 to 8,000 of the electrolyte. The adjuvant solution should preferably be about neutral, that is, in the pH range of 6.0 8.0 to avoid destruction of active agents which may be mixed with the adjuvant solution. Many active agents, antigens for example, are degraded in acidic or basic media.

The polymers employed as adjuvants include the class of colloidally water-soluble acrylic acid polymers cross-linked with polyhydroxy compounds in which the hydrogen atoms of at least some of the hydroxy groups have been replaced by unsaturated aliphatic groups,-

e.g., polymers of acrylic acid cross-linked with from 0.75 to 2.00% of polyallysucrose and polyallylpentaerythritol, as described in U.S. Pat. No. 3,178,350. Typical of these compounds are those made by the B. F. Goodrich Chemical Company and designated by the trademark Carbopol. Carbopol-934 is the acrylic acid polymer cross-linked with approximately 1% polyallylsucrose. Carbopol-934 is the preferred adjuvant compound although other Carbopols such as Carbopol-940 and Carbopol-941 are also acceptable. The concentration of the polymer in the adjuvant solution can vary from about 0.10 per cent to about 3 per cent or more. The higher concentrated solutions are of particular advantage for mixing with solutions of an active agent, for example bacterins, which cannot be diluted apprecia bly without lowering the potency of these bacterins to levels unacceptable to the U.S. government regulatory agencies. Higher concentrations of the polymer can be diluted by mixing with a volume of a solution of an active agent which brings the concentration of polymer in the resulting adjuvant-active agent mixture to a lower level which is sufficient to produce an adjuvant effect. The final concentration of the polymer in the mixture with the active agent should be at least 0.10% and can be as high as about 1.0%, preferably in the range of about 0.20 to about 0.50%. If the active agent is in dry form, it is merely dissolved or suspended in the polymer 4 solution of a concentration known to give good adjuvant effects, usually about 0.2 to 0.5% or more.

Solutions of the polymer in a pH range of 6-8 are very viscous even at a concentration of about 0.2% and at about 0.5% or higher they form gels. It becomes almost physically impossible to mix an active agent into gels containing 0.5% or higher of polymer and achieve a homogenous mixture, particularly on a production scale. Mixtures of an active agent and the polymer in which the concentration of the polymer is about 0.2% or more are generally too viscous to draw into or expel easily through a needle of a hypodermic syringe.

These drawbacks for using an otherwise effective polymer as adjuvant are overcome by the use of a mixture of the polymer and an amount of electrolyte sufficient to reduce substantially the viscosity of the polymer solution to useful levels, e.g., about 500 to 50,000 cps, preferably about 500 to about 40,000 cps. The amount of electrolyte which should be added will generally be dictated by the initial viscosity of the polymer at the intended concentration in the active-adjuvant solution. The amount of electrolyte generally should not greatly exceed isotonicity in the final adjuvant-active agent mixture. Usually lesser quantities will be required to bring the viscosity of the mixture down to a useful level. Any physiologically acceptable electrolyte may be used, as long as it is physiologically acceptable and thus not detrimental to the host. Examples are alkalimetal, alkaline earth and ammonium salts of mineral and organic acids, e.g., sodium chloride and bromide; potassium chloride and bromide; ammonium, magnesium and calcium chloride; sodium, potassium, ammonium and magnesium sulfate; sodium and potassium mono-, di-, and tribasic phosphates; sodium and potassium acetates, sodium and potassium propionates; sodium and potassium succinates; sodium and potassium maleates; sodium and potassium tartrates; sodium and potassium lactates; ammonium, sodium and potassium citrates; sodium potassium and magnesium gluconates; and sodium ascorbate. Of these, sodium phosphates, sodium chloride, sodium citrate and magnesium sulfate are preferred. In some instances the active agent itself may be ionic and will effect a lowering of viscosity. Nevertheless, sufficient electrolyte should be incorporated in the polymer adjuvant solution to lower its viscosity to a level which will allow the solution to be mixed relatively easily with the active agent.

The viscosity of the polymer-electrolyte adjuvant solution, prior to mixing with the active agent, regardless of whether the active agent is in the dry form or in a solution or suspension, should not be greater than about 50,000 cps as measured in the following manner: Approximately 400 ml. of the adjuvant solution is placed in a 600 ml. beaker and a No. 7 spindle is placed into the solution and rotated at 10 rpm while recording the reading on a Brookfield viscometer, model RVT at 25C i 0.5C. To achieve a viscosity of about 50,000 cps or lower, for ease in mixing the adjuvant solutions with solutions or suspensions of an active agent, particularly when higher polymer concentrations are involved, an electrolyte is mixed with the polymer or aqueous solution thereof in an amount which will lower the visocity of the adjuvant solution to 50,000 cps or less, preferably about 40,000 cps or less, more preferably up to about 32,000 cps. For ease in passing through hypodermic needles, the final viscosity of the solution of the mixture adjuvant and active agent should generally be no more than two thousand centipoise.

' In US. Pat. No. 3,178,350, there is disclosed an adjuvant solution containing only Carbopol. Good adjuvant properties were obtained using Carbopol at 0.25 and 0.50%. The viscosities of these solutions at pH 7 were 12,000 and 60,000 cps, respectively using a No. 7 spindle and a speed of 10 rpm. Although it required some effort, particularly with the 0.5% solution, they were finally mixed with dried influenza vaccine, for example, and the mixtures could be made to pass through a 20 gauge needle but only with difficulty. For example, with the 0.25% solution, it requires approximately 40 seconds to draw 5 ml. into a syringe and about seconds to expel the 5 ml. The 0.5% gel could not be drawn through the needle. If 5 ml. was placed into a syringe, it required about seconds and considerable pressure to expel the contents through the needle. After adding sodium phosphates to similar solutions in amounts to make them about half isotonic, the viscosities were 400 cps and 600 cps, respectively. These solutions could be readily mixed with dried vaccine and made to pass through 20 gauge needles with ease and rapidity. The adjuvant effect did not diminish, even though the viscosity had been greatly decreased.

The term active agent as used herebefore is meant to include therapeutic agents of many types whose effect may be prolonged or enhanced by their inclusion with the adjuvant polymers. Among these are antigenic substances which stimulate the production of antibodies and include viruses such as influenze (monovalent or polyvalent, human or equine), measles, mumps, poliomyelitis, canine distemper, encephalomyelitis, rabies, foot mouth disease, bovine diahrrea, infectious bovine rhinotracheaitis and Newcastle disease viruses; toxoids, such as those of Clostridium perfringens (Types B, C, and D), Clostridium tetani, and diphtheria; bacterins, such as those of Clostridium chauvoei, Clostridium septicum, Clostridium hemolyticum, Clostridium novyi, Clostridium sordellii, Leptospira, streptococcus, staphlococcus, pneumococcus, pseudomonas, l-I. pertussis, fowl cholera, and erysipelas; rickettsia, such as rocky mountain spotted fever, typhus, Q fever; allergens, such as pollens, dust, danders or ex-' tract of same; and venoms, such as bee sting and snake venoms, and the like.

. The adjuvant solutions may be prepared by several procedures. In one method, the electrolyte and polymer are intimately blended in the dry state, then added gradually to water, preferably warmed to about 50 to 70C., while stirring at about 1-2000 rpm. Following dissolution of the mixture, the pH is adjusted to the desired value, somewhere in the range of 6-8, preferably about 6.5 7.5, by the addition of an aqueous solution of a base such as sodium hydroxide or ammonium hydroxide. Additional water is added to bring the polymer to the desired final concentration and the solution may then be sterilized by conventional means. The adjuvant solution may also be prepared by blending an electrolyte with a polymer which has been neutralized with a base such as sodium or ammonium hydroxide and isolated in a solid state. The blend is readily dissolved in the appropriate amount of water. The preblending of the polymer and electrolyte greatly facilitates the dissolution of the polymer since high viscosities are not encountered as would be the case when polymer is first dissolved and then the electrolyte is added.

Solutions or suspensions of the adjuvant solution in combination with an active agent may then be prepared. In those cases where the active agent is added as a solid, the concentration of the polymer in the adjuvant solution will generally be in a lower range, most usually about 0.2 to 0.5%, so that the final concentration of the polymer in the adjuvant-active agent mixture will be the same as in the adjuvant solution. When the adjuvant solution is to be mixed with an active agent which is in the form of a solution or suspension, such as soluble bacterin or virus vaccine solutions, then the concentration of the polymer in the adjuvant solution will usually be much greater, generally in the range of about 0.5 to 3%'or higher, so that the resulting mixture of one volume of the adjuvant solution with one to ten or more volumes of vaccine solution, for example, will contain the adjuvant polymer at a lower but still very effective level. In effect, the potency of the vaccines are not materially reduced by this dilution with the polymer adjuvant solution. This is very important when one is dealing with vaccines whose potencies are borderline and which would be impossible or commercially impracticable or detrimental to concentrate by means such as ultrafiltration or dialysis. An alternative to mixing very concentrated solutions of polymer adjuvant with vaccines with borderline potencies is to dissolve a blend of neutralized polymer and electrolyte directly into the vaccine solution. Generally, however, it is more convenient and reliable in large production batches to mix the polymer as a solution with the vaccine solution.

Although not necessary or essential for the adjuvant effects of the polymer in the polymer-electrolyte solution, other materials may be included. For example, various physiologically acceptable emulsifiers may be added to the water to speed up the dissolution of the polymer when preparing the adjuvant solution. The emulsifier may be a non-ionic compound, such as Tween 80 (polyoxyethylene sorbitan monooleate), Span 20 (sorbitan monolaurate) or others of this type, alone or in combinations or mixed with vegetable oils. The emulsifier, when used, generally does not exceed about 0.05% in the final adjuvant-active agent mixture. The inclusion of buffers is sometimes desirable for mantaining pH stability of the adjuvant solution. Alkali metal phosphates, such as monosodium and disodium phosphates are preferable. They not only serve as a buffer but being electrolytes also contribute to the lowering of viscosity of the polymer solution. Phosphates may be used in combination with other electrolytes such as sodium chloride, the phosphate acting as a buffer and both effecting a lowering of viscosity. Nonence appears to provide a more elegant appearance to the solution. Although concentration may vary, a preferred concentration appears to be about 1% in the adjuvant-active agent mixture. Preferred adjuvant-active agent compositions of this invention are those adapted for intramuscular (I.M.), intraperitoneal (I.P.) and/or subcutaneous (SQ) administration.

The invention thus relates to improved adjuvant solutions and to injectable mixtures thereof containing biologics. The adjuvant solutions comprise about 0.2% to about 3.0% of a substantially neutral, colloidally watersoluble acrylic acid polymer cross-linked with a polyalkylsucrose or polyallylpentaerythritol and a physiologically acceptable electrolyte. The electrolyte is present in an amount effective to lower substantially the viscosity imparted to the adjuvant solution by the polymer to a maximum of about 2,000 cps for a 0.2% solu- 8 tion with specific active agents are hereinafter described.

ADJ UVANT SOLUTIONS OR CARBOPOL All weights are expressed in grams of Carbopol or electrolyte in 100 ml. of solution. pH was adjusted with 20% NaOH.

Viscosity at 25 05C.

Carbopol" Scale l-l Example 934! Electrolyte pH Spindle RPM Reading X Factor cps l 0.25 none 6.8 7 l0 3 4000 12,000 2 0.5 none 6.8 7 l0 15 4000 60,000 3 25 none 6.65 7 10 41.5 4000 166,000 4 0.25 0.47 N21 HPO 6.9 7 100 l 400 400 0.23 NaH PO H O 5 0.5 0.94 Na HPO, 6.9 7 1.5 400 600 0.46 NaH PO .H O 6 2.5 4.7 Na HPO 6.95 7 l0 12 4000 48.000

2.3 NaH PO .H O 7 2.5 9.4 Na- -HPO 7.0 7 l0 8 4000 32,000

4.6 NaH- PO H 0 8 2.5 2.5 NaCl 7.0 7 l0 10 4000 40,000 9 2.5 5.0 NaCl 6.60 7 10 4.5 4000 18.000 10 2.5 1.2 MgSO 7.0 7 10 8 4000 32.000 11 2.5 5.0 Na citrate 65 7 10 13.5 4000 54,000

(dihydrate) 12 2.5 10.0 Na citrate 6.7 7 10 6.5 4000 26,000

(dihydrate) Carbopol 940 13 2.5 5.0 NaCl 6.9 7 l0 10 4000 40.000

Carbopol 941 14 2.5 2.5 NaCl 6.8 7 10 7.5 4000 30,000

"P stands for pharmaceutical grade. 7

*Snlution also contains equal parts Tween 80 and Spun (total 0.1 g). 1 m1. cottonseed oil and 2.5 g. gelatin.

the biologic should contain about 0.2 to 1.0% of the polymer, preferably about 0.2 to 0.5%. The injectable composition should contain an amount of electrolyte relative to the polymer concentration which produces a viscosity of up to about 2,000 cps. Thus, for example, a solution containing 0.5% of the polymer only would have a viscosity of about 60,000 cps and would be too viscous to mix conveniently with a biologic solution. If sodium phosphate is added to this solution to give a salt concentration of 1.4% (about isotonic), the viscosity of the resulting solution drops to about 600 cps or less and this solution can be readily mixed with a biologic. a 50:50 mixture of this adjuvant solution and a biologic solution would produce an injectable composition containing 0.25% of the polymer and 0.7% of the phosphate electrolyte (about one-half isotonic) and having a viscosity of about 400 cps or less. If, for example, the adjuvant solution contains 2.5% of the polymer and no electrolyte, the viscosity is about 166,000 cps and the adjuvant could not be mixed with a biologic. With the addition of phosphate to make a concentration of 7.0% in the adjuvant solution, the viscosity drops to about 48,000 or less. This solution has a low enough viscosity that it can be mixed with a solution of a biologic. Mixing nine parts of a biologic solution with one part of this adjuvant solution results in a final concentration of 0.25% of the polymer and 0.7% of the Phosphate. The viscosity of the final mixture is about 400 cps or less, well below what is acceptable for ease in injecting an adjuvanted biologic solution.

In order to more clearly disclose the nature of the present invention, specific examples illustrating typical compositions of the adjuvant solutions and combina- MIXTURES OF CARBOPOL ADJ UVANT WITH ACTIVE AGENTS EXAMPLE l5 Influenza Virus The following vaccine preparations were made:

A. Bivalent equine influenza vaccine solution containing formalin killed Strain A (A/Equine 1/Pa./63 strain) and Strain A (A/equine 2/Miami/63 strain) mixed with an equal volume of 1.4% sodium phosphate buffer (control vaccine, no adjuvant present).

B. Same as A. but replacing phosphate buffer with an equal volume of a 2.2% Al(OI-I) suspension.

C. Same as A. but replacing the phosphate buffer with an equal volume of the Carbopol-sodium phosphate electrolyte adjuvant solution of Example 5.

D. Dried human influenza vaccine (PR-8) mixed with the Carbopol solution of Example 2 which contained no electrolyte.

Test 1. Three groups of 24 Swiss Webster mice were inoculated subcutaneously with 0.5 ml. of either vaccine preparation A, B, or C. Fourteen days later 12 mice from each group were bled, the sera were pooled and the remaining 12 mice in each group were given a second 0.5 ml. inoculation. Pooled sera from the second groups of 12 were collected after 14 days. A fourth group of 24 mice were given only one 0.5 ml. dose of the C vaccine preparation; serum was collected from 12 mice on the 14th day and on the 28th day. Antibody titers were obtained on the pooled sera by the standard hemaglutination inhibition test (I-IAI).

Test 2. A group of 8 rats was inoculated subcutaneously with 0.5 ml. of the D vaccine preparation, serum was collected on the 14th day, and analyzed by the HM test.

Days Post l-lAl Titer Against Vaccine Preparation inoculation Strain A Strain A A (Control no adjuvant) 14 128 2 (2 inoculations) 28 128 16 B (A1(OH);, adjuvant) 14 128 2 (2 inoculations) 28 256 16 C (Carbopol adjuvant with electrolyte) 14 256 2 (2 inoculations) 28 512 64 C (Carbopol adjuvant 14 256 32 with electrolyte) 28 512 128 (l inoculation) D (Carbopol adjuvant Strain A no electrolyte) 14 256 (1 inoculation These results show the adjuvant effect of Carbopol to 20 be superior to that of Al(Ol-l) with respect to influenza EXAMPLE 17 virus vaccines and demonstrate that the adjuvant effect of Carbopol is not diminished even though the viscosity of the Carbopol vaccine mixture has been decreased by the inclusion of the phosphate electrolyte.

EXAMPLE 16 Equine Influenza Virus Horses were inoculated intramuscularly with 1.0 ml. of a 50-50 mixture of the bivalent equine influenza (Strains A and A vaccine solution and the Carbopolphosphate electrolyte adjuvant of Example 5. Serum samples were obtained on days 0, 21, 41 and 63. All horses showed slight to moderate pre-existing antibody levels due to previous infections with the viruses. Earlier studies on two groups of 13 horses had demonstrated little or no antibody response to either strain could be elicited up to 63 days following injection of the same virus in phosphate buffer and in Al(Ol-l) Days Post l-lAl Titers Against Horse Inoculation Strain A, Strain A These results from testing on another species further confirm the good adjuvant properties of a Carbopolelectrolyte mixture with a vaccine.

Clostridium chauvoei Bacterin C. 87 parts resuspended cells 13 parts of 2.2% A1- (OH) suspension.

D. 90 parts whole culture 10 parts of the Carbopolphosphate electrolyte adjuvant of Example6.

E. 90 parts supernatant fluid 10 parts of the Carbopol-phosphate electrolyte adjuvant of Example 6.

F. 90 parts resuspended cells 10 parts of the Carbopol-phosphate electrolyte adjuvant of Example 6.

Six groups of 10 guinea pigs were injected subcutaneously with 0.5 ml. of one of the six vaccine-adjuvant preparations on day 0 and day 10. At day 21, all were challenged with C. chauvoei spore IRP128. Survivors were determined on day 24. This procedure is Standard Requirement B-23 SAM-200 of the US. Department of Agriculture, Vet. Biol. Division and of the animals must survive in order for the vaccine to pass the test.

Mixture Survival A 8/ 10 B 7/10 C 6/ 10 D 10/ 10 E 10/ 1 0 F 10/ 1O Controls (no bacterin) 0/10 C. chauvoei vaccines containing no adjuvant seldom will pass potency test requirements since potencies of production lots which have not been concentrated by some means are generally borderline. Adjuvants are therefore most desirable for such vaccine preparations. The above experiment demonstrates how it is possible to take advantage of the good adjuvant properties of Carbopol without significantly lowering the potency per ml. of the bacterin. This is accomplished by adding only a very small volume of a very concentrated solution of the Carbopol to the bacterin solution. Mixing the bacterin solution with the concentrated Carbopol solution is possible only by virtue of the greatly reduced viscosity of the Carbopol solution resulting from the inclusion of the electrolyte. Without the electrolyte, the 2.5% Carbopol solution would exist as a stiff gel which could not possibly be mixed with the bacterin solution without a great deal of difficulty, require a prolonged period of time and render the operation commercially impracticable.

EXAMPLE l8 Clostridium sordellii Toxoid Strain 3822-2 of Clostridium sordellii was grown in beef broth and killed with formalin. The culture was centrifuged and the supernatant fluid was collected. Ninety parts of this fluid was mixed with 10 parts of the Carbopol-phosphate electrolyte adjuvant of Example 6. Ten mice were injected subcutaneously with 0.5 ml. of the mixture on days and 14 and challenged on the 28th day with C. sordellii spore.

Mixture Survival C. sordellii toxoid Carbopol 8/10 EXAMPLE l9 Clostridium septicum with C. chauvoei Bacterin Various mixtures of C. chauvoei and C. septicum were prepared as follows:

A. 2 parts C. chauvoei whole culture with 1 part C. septicum whole culture.

B. 1 part each of the two whole cultures plus the paste from centrifugation of 1 part chauvoei whole culture.

C. Paste from 1 part chauvoei and 1 part septicum whole culture.

D. Equal parts of the whole culture of each.

Nine parts of each mixture were then mixed with one part of the Carbopol-phosphate electrolyte adjuvant of Example 6. Groups of hamsters and 10 guinea pigs were inoculated with 0.2 ml. of the bacterin-adjuvant mixtures on days 0 and 10. On the 21st day, the 10 guinea pigs were challenged with C. chauvoei spore and the 5 hamsters were challenged with C. septicum spore in each group. Control animals were challenged with one-tenth the spore concentration the test animals received.

Bacterin-Adjuvant Good adjuvant effects were demonstrated for Carbopol 934P with respect to C. septicum. Results from Examples 18 and 19 further show the advantages of being able to mix concentrated Carbopol solutions (because of the viscosity lowering effect of the electrolyte) with two other Clostridium bacterins whose potencies are normally borderline and obtain good adjuvamt effects. Without adjuvant of any kind, vaccine preparations of C. sordellii or C. septicum seldom pass potency test requirements.

The allergist generally employs commercially available solutions of extracts of the various allergens at their most concentrated form. Included in kits containing a specific allergenic solution are a number of separate vials containing specific volumes of a diluent, e.g., sterile distilled water, or a buffered salt solution of phosphates, with sodium chloride or some other buffer, such as sodium carbonate.

The following examples illustrate the preparation of adjuvants of this invention, both as solutions and in dried form, and their combination with allergens or antigens at the time of use. Example 19 illustrates the use of a mixture of Carbopol and one of the commonly used diluents for allergens. It also illustrates the combination of a solution form of the adjuvant, either with a dried allergen or with a solution of the allergen. Example 20 illustrates a sterile lyophilized form of the adjuvant and its use to prepare a vaccine. Example 21 describes the preparation of antigenic-adjuvant vaccines immediately prior to use.

EXAMPLE 19 A. Preparation of Adjuvant Solution B. Preparation of Allergenic Solution with Adjuvant The above adjuvant solution in a vial containing 5.0 ml. was transferred asceptically by syringe to a vial containing a lyophilized allergen, for example, ragweed (small) obtained by extraction of ragweed pollen. Following reconstitution of the allergen into the adjuvant solution which results in a 1:10 dilution, 0.5 ml. of the resulting solution was then transferred into a vial containing 4.5 ml. of the adjuvant solution to give a 1:100 dilution. This procedure was repeated with other vials containing 4.5 ml. adjuvant solution until a dilution of 1: 100,000 was reached. An injection of the most dilute allergenic solution is made followed, at appropriate weekly time intervals, by injection of the next more concentrtated solution until the tolerance level to the most concentrated allergenic solution is reached. Injections of any one of the serially diluted solutions can vary, usually from 0.02 to 0.5 ml. depending on the sensitivity of the individual patient.

When the allergen is supplied as a solution by the manufacturer, the above procedure is followed with the exception that a 0.5 ml. portion of the allergenic solution at its most concentrated level is first added to a vial containing 4.5 ml. of the adjuvant solution. Subsequent serial dilutions can then be made as described above.

EXAMPLE 20 A. Preparation of Dried Adjuvant A blended mixture of 25 g. of Carbopol 934? and 23 g. of monosodium phosphate monohydrate was slowly added with stirring to about 800 ml. of distilled water warmed to about 75C. Following dissolution, 47.25 g.

of disodium phosphate was added and after cooling to room temperature, the pH was adjusted to about 7.0 with 20 percent sodium hydroxide solution and the volume then made up to 1 liter with distilled water. Aliquots, for example 0.4 to 1.0 g. aliquots, were placed in vials and subjected to lyophilization. The vials were then sealed and subejcted to heat sterilization.

B. Preparation of Vaccine EXAMPLE 21 A. Preparation of Virus Influenza virus, Type A, strain PR-8, was harvested from the allantoic cavity of embryonated hen eggs following standard procedure. The allantoic aluid was inactivated with formalin and lyophilized in vials so that each vial contained 88.8 mg. of dried virus.

B. Preparation of Adjuvant Solution While stirring about 800 ml. of distilled water held at about 70 to 75C., a blended mixture of 2.5 g. Carbopol 934P, 4.7g. disodium phosphate and 2.3 g. monosodium phosphate monohydrate was added gradually thereto. Stirring was continued until dissolution was complete. The solution was cooled to room temperature and a percent solution of sodium hydroxide was added until the pH reached approximately 7.0. Distilled water was then added to bring the volume to one 14 liter. The solution of adjuvant was then subjected to heat sterilization after aliquots were placed in sealed vials.

C. Preparation of Vaccine A six milliliter aliquot portion of the adjuvant solution contained in a sealed vial, obtained according to Step B, was transferred by a sterile syringe to a vial containing 88.8 mg. of dried influenza virus. The mixture was shaken to dissolve the virus and the solution was then ready for injection.

What is claimed is:

1. A sterile lyophilized powder, for reconstitution as an adjuvant for antigens which stimulate the production of antibodies by mixture with sterile water and with such antigens to form sterile injectable aqueous adjuvant-antigen solutions, consisting essentially of a mixture of a colloidally water-soluble substantially neutral polymer of acrylic acid cross-linked with from 0.75 to 2.00% of polyallylsucrose or polyallylpentaerythritol, and an amount of a physiologically acceptable electrolyte effective to lower substantially the viscosity imparted by the polymer to aqueous solutions of the adjuvant to a maximum of about 2,000 cps. for a 0.2% solution and a maximum of about 50,000 cps. for a 3% solution thereof.

2. An adjuvant according to claim 1, wherein the electrolyte is present in a molar weight proportion to the polymer of about 800:1 to 8,00021. I

3. An adjuvant according to claim 1, wherein the electrolyte is at least one of sodium phosphates, sodium chloride, sodium citrate and magnesium sulfate.

4. An adjuvant according to claim 1, wherein the electrolyte is one or more sodium phosphates.

5. An adjuvant according to claim 2, wherein the electrolyte is at least one of sodium phosphates, sodium chloride, sodium citrate and magnesium sulfate.

6. An adjuvant according to claim 2, wherein the electrolyte is one or more sodium phosphates.

7. An adjuvant according to claim 1, wherein the polymer is cross-linked with polyallyeucrose.

8. An adjuvant according to claim 7, wherein the electrolyte is at least one of sodium phosphates, sodium chloride, sodium citrate and magnesium sulfate. v

9. An adjuvant according to claim 7, wherein the electrolyte is one or more sodium phosphates.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION I PATENT NO. 3,920,811

DATED 3 November 18, 1975 INVENTOR(S) Lloyd J. Lund It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shqwn below:

Column 1 line 10: Change "polyallylsucros" to --polyal1y1sucrose-.

Column 8, line 3: Change "OR to --OF--,

Column 10, line 28: Change "pasts" to --paste--.

Column 13 line 16, Change "subcted" to --subjected--.

Column 14, line 42, Change "polyallyeucrose" to --polyal1y1sucroSe-.

Signed and Scaled this twenty-fourth D ay or February 1 9 76 [SEAL] A ttest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer v (ommissr'mrer uflalenrs and Trademarks 

1. A STERILE LYOPHILIZED POWDER, FOR RECONSTITUTION AS AN ADJUVANT FOR ANTIGENS WHICH STIMULATE THE PRODUCTION OF ANTIBODIES BY MIXTURE WITH STERILE WATER AND WITH SUCH ANTIGENS TO FORM STERILE INFECTABLE AQUEOUS ADJUVANT-ANTIGEN SOLUTIONS, CONSISTING ESSENTIALLY OF A MIXTURE OF A COLLOIDALLY WATER-SOLUBLE SUBSTANTIALLY NUETRAL POLUMER OF ACRYLIC ACID CROSS-LINKED WITH FROM 0.75 TO 2.00% OF POLYALLYSUCROSE OR POLYALLYLPENTAERYTHRITOL, AND AN AMOUNT OF A PHYSIOLOGICALLY ACCEPTABLE ELECTROLUTE EFFECTIVE TIO LOWER SUBSTANTIALLY THE VISCOSITY IMPARTED BY THE POLYMER TO AQUEOUS SOLUTIONS OF THE AFJUVANT TO A MAXIMUM OF ABOUT 2,000 CPS FOR A 0.2% SOLUTION AND A MAXIMUM OF ABOUT 50.000 CPS. FOR A 3% SOLUTION THEREOF.
 2. An adjuvant according to claim 1, wHerein the electrolyte is present in a molar weight proportion to the polymer of about 800: 1 to 8,000:1.
 3. An adjuvant according to claim 1, wherein the electrolyte is at least one of sodium phosphates, sodium chloride, sodium citrate and magnesium sulfate.
 4. An adjuvant according to claim 1, wherein the electrolyte is one or more sodium phosphates.
 5. An adjuvant according to claim 2, wherein the electrolyte is at least one of sodium phosphates, sodium chloride, sodium citrate and magnesium sulfate.
 6. An adjuvant according to claim 2, wherein the electrolyte is one or more sodium phosphates.
 7. An adjuvant according to claim 1, wherein the polymer is cross-linked with polyallyeucrose.
 8. An adjuvant according to claim 7, wherein the electrolyte is at least one of sodium phosphates, sodium chloride, sodium citrate and magnesium sulfate.
 9. An adjuvant according to claim 7, wherein the electrolyte is one or more sodium phosphates. 